Hi Steph,
Thank you very much for your message.
Westport is a town in the civil parish of Oughaval-I wonder could this be what Cuhol is referring to? It is likely that the correct name was lost in translation and perhaps this is what was written down instead.
http://www.irishtimes.com/ancestor/fuses/townlands/index.cfm?fuseaction=TownlandsInCivil&civilparishid=1788&civilparish=Oughaval&citycounty=Mayo
You could try looking in church records in the parish to see if you can find anything pertaining to the family. Most Catholic records are held locally so you may need to write to the local parish priest for possible assistance. One website that you may find useful is the Irish Times where they give an overview of what records are available in specific parishes. It also shows you where copies of the records are available. For Aughaval parish, follow this link:
http://www.irishtimes.com/ancestor/fuses/rcparishmaps/index.cfm?fuseaction=showidrecords&CityCounty=Mayo&parish=Aughaval&churchid=1043
As you can see from the above link the South Mayo Family History Centre have copies available.Here is their email if you would like to contact them, however a fee may apply: soumayo@iol.ie
I did find a record of a John Henaghan in Griffith?s Valuation. This is a land record pertaining to Ireland 1848-64. He was recorded in Oughaval parish in 1855-was your John still in Ireland t that time?
http://www.askaboutireland.ie/griffith-valuation/index.xml?action=doNameSearch&familyname=Henaghan&firstname=&offset=120&countyname=MAYO&parishname=&parishname&unionname=&baronyname=&totalrows=136&PlaceID=0&wildcard=
Some other websites that you may find useful are:
The National Archives of Ireland http://www.nationalarchives.ie/genealogy1/genealogy-records/introduction/
The National Library of Ireland http://www.nli.ie/en/family-history-introduction.aspx
Family Search: www.familysearch.org
Irish Genealogy Tool kit: www.irish-genealogy-toolkit.com
Mayo: http://www.mayo.ie/dnn/
Genealogy Links: http://www.genealogylinks.net/uk/ireland/mayo/index.html
From Ireland: www.from-ireland.net
Kind regards,m
Genealogy Support